According to the National Cancer Institute, an estimated 234,000 new cases of prostate cancer will be diagnosed in the United States alone this year. Of these cases, more than 27,000 deaths due to prostate cancer are expected to occur this year. Following skin cancer, statistics show that prostate cancer is the most common cancer among American men.
Currently, medical professionals use a transrectal ultrasound-imaging device (TRUS) probe to acquire and guide prostate imaging and biopsy. The TRUS probe is the most widely accepted technique for prostate applications due to its simplicity, high specificity, and real time nature. In such an application, the TRUS probe may be inserted into the rectum of a patient to generate an image. Such images may be utilized to take one or more biopsies from a prostate location of interest and/or implant radioactive seeds at one or more desired locations in a brachy-therapy procedure. The TRUS probe may also be used in conjunction with other medical imaging applications, including cyrotherapy, photo-dynamic therapy, or a combination of these therapies and/or fusion-guided biopsies. With all of these applications, however, precise and repeatable TRUS probe placement and guidance is of utmost importance to achieve accurate imaging and rendering of the applicable therapy.
Prior art describes a number of methods and devices for assistance in guiding and placing the TRUS probe for imaging, biopsy, and therapy. Generally, these prior art devices utilize several mounting, stepping, and rotating devices for various commercially available TRUS probes. These tracking assemblies are typically stand-alone devices that utilize a combination of linkages and tracking mechanisms for monitoring the spatial position of a supported probe.
Such tracking assemblies are often not adapted for significant positional adjustment relative to the patient's body, as located on an examination table or a gurney bed. In order to “pre-fit” or “pre-position” such a tracking assembly to a patent, it has often been necessary to position the patient relative to the tracker assembly. In some instances, such limited tracker movement has impeded the accommodation of patients of varying heights and weights.
While extending the range of motion of the tracker assembly would apparently alleviate such pre-positioning difficulties, such expanded range of movement raises other difficulties. For instance, many tracking assemblies include a series of rotatively coupled armatures that allow extending and retracting the tracking assembly in one or more dimensions. To expand the range of movement of such devices, the length of the armatures would have to be increased. Considering the limited space often available in medical examination rooms, the armatures on any given tracking assembly would be prohibitively long to accommodate the movement often necessary to preposition the tracking assembly relative to a patient.
Beyond limited space constraints, increasing armature length to achieve necessary movement may introduce an unacceptable level of distortion into the spatial tracking of the tracking assembly.